Automatic switch for air-compressor motors.



W. J. STARK.

AUTOMATIC SWITCH FOR AIR COMPRESSOR MOTORS.

APPLICATION FILED JUNE 5. 1917.

Patented Feb. 11, 1919.

Immron MY/Yam WILLIAM JACOB STARK, 0F VANCOUVER, BRITISH COLUMBIA, CANADA.

AUTOMATIC SWITCH FOR AIR-COMPRESSOR MOTORS.

Specification of Letters Patent.

Patented Feb. 11, 1919.

Application filed June 5, 1917. Serial No. 173,067.

To all whom 2'25 may concern:

Be it known that 1, WILLIAM JACOB STARK, a subject of the King of Great Britain, and a resident of the city of Vancouver, in the Province of British Columbia, Canada, have invented certain new and useful Improvements in Automatic Switches for Air-Compressor Motors, of which the following is a specification.

Hy invention relates to improvements in automatic switches for motors operating pressure generating machines, such as motors used for driving air compressors or the like, and the object of my invention is to provide a simple and eflicient means for automatically throwing out the switch controlling the electric current by which the motor is operated in the event of the pressure in the air line falling below, or rising above, the normal or through the air line being fractured or becoming leaky, thus eliminating the danger of fire through the motor continuing to run after the damage has taken place, a frequent occurrence at the present time.

I attain this object by the construction illustrated in the accompanying drawings in which,

Figure 1 is a side elevation of my device.

Fig. 2 is a front view.

Similar reference numerals indicate similar parts throughout the several views.

1 indicates a portion of the air line, which is suitably connected to the electric motor driven pump or compressor 28, and to the air tank 2, shown in Fig. 1. 3 indicates a shut-01f valve on the air line, from which extends a pipe or cylinder 4, the bore of which is in communication with the air line 1 when the valve 3 is open and is fitted with a piston 5 provided with a piston rod 6 extending upwardly through a packing nut 7. The upper end of the piston rod 6 is connected to a bar 8 carried by a bracket 9 secured to the pipe 4, which bar is fulcrumed on a pin 10, its free end extending through a slot 11 in a suitably supported plate 12. The bar is provided with a number of holes 13, from one of which dependsa weight 14.

15 and 16 indicate suitably secured brackets, in which is'rotatably' mounted a roller 17 provided at one end with a plurality of teeth 18, with which teeth a suitably mounted spring member 19 normally engages, which member is vertically movable in a guide bracket 20 and is in connection with the bar 8 by means of a wire 21, the wire being led from an eye 22 formed in the member 12 to one of the holes 13 in the bar. 23 indlcates a wire or rope secured at one end to and wound several times around the roller 17, and to the free endof which is secured a weight 24, while 25 indicates a wire or rope also having one end secured to and wound around the roller 17, its free end being connected to the switch lever 26, the switch, indicated by the numeral 27 in Fig. 1, being of the usual type. The device is arranged and set as shown in Figs. 1 and 2, the piston 5 being maintained in its upinost position by the normal pressure in the pipe 4. In the event of the pressure falling in the air line, through accident thereto or from any other cause, to below the normal, the piston 5 drops, as also does the weight 14 and therefore the bar 8. The dropping of the bar pulls the wire 21 and therefore the spring member 19 out of engagement with-the teeth 18 of the roller 17 thus allowing the roller to be rotated by the weight 24, which drops suddenly when the member 19 is withdrawn from the teeth 18. The revolving roller winds up the slack of wire 25, the sudden jerk of which, when taut, pulls out the switch lever 26, thus breaking the circuit and stopping the motor.

lVhen the damage to the air line hasbeen repaired and the pressure therein reestablished, the piston 5 raises the bar 8, and the weight 14 to their normal positions, when the device may be re-set and the spring member 19 reengaged with the teeth 18 to prevent inadvertent rotation of the roller 17 The description of the device and its operation up to this point has been made with particular reference to the falling of the pressure in the air line, but it is desirable that the device should also be capable of operating to throw the switch in the event of the pressure rising above the normal. In the first instance the bar 8 when at its highest position bears on the top end of the slot 11, as it is then only required to drop to pull out the switch lever 26, but in the latter instance the bar is positioned midway of the slot 11, as it is then designed to rise or fall in the slot, according as the pressure rises or falls above the normal, and it, the bar, is then maintained in mid position by means of suitable springs 29 and 30 inserted in the slot above and below the bar. A sheave 31 is rotatably mounted on the lower end of the plate 12 and around this sheave a wire 32 is led, one end of the wire being connected to the bar 8 and the other end to the spring member 19. It will now be'seen thaton the bar 8 rising through increased pressure in the air line the spring'member 19 will be drawn out of engagement with the teeth of the roller 17 by means of the Wire 32, so that the switch lever 26 will be pulled out in the manner hereinbefore described. On the pressure falling to normal, the device may be re set as before, when it will be ready to operate again to throw the switch shouldtheair pressure rise or fall above the normal.

Although I have described my invention in itsir'elation to an air compressor I do not wish to limit myself to its use for this purpose alone, as it will be apparent that it may be applied, with equal facility, to lines carrying pressure other than air, such as hydraulic pressure, steam pressure, or the like, and it is intended, therefore, that all matter contained in the accompanying specification and drawings shall be interpreted as illustrative andnot in a limiting sense.

YVhatl claim as my invention is 1. In apparatus of the class described,in combination, a pressure line, a motordriven pressure generator therefor, a switch for said ,motor, a roller provided on one end with Ia plurality of teeth arranged circularly, aspring member normally engaging said teeth whereby rotation of the roller is prevented, normally slack flexible connection having one end secured to the switch lever and the other end wound on the roller,

' means operated by loss of pressure in said line for disengaging said spring member from said teeth, and means for then rotating the said roller;

2. In apparatus of the class described, in combination, a pressure line, a motor driven pressure generator therefor, a switch for said motor, a roller on which is wound a rope having a weight suspended from its free end, means for holding said roller so as to support the said weight in the suspended position, a normally slack" flexible connection having one end secured to the switch lever and the otherend wound on the roller,'and means operated by loss of pressure in the said line for'freeing the roller.

3. In apparatus of the class described, in combination, a pressure line, a motor driven pressure generator therefor, a switch for said motor, a roller provided at one end with a plurality of teeth arranged circularly and having wound thereon a rope from the free end of which a weight is suspended, a spring member normally engaging said teeth whereby rotation of the roller-is prevented, a normally slack flexible connection having one end secured to the switchlever and the other end wound on the roller, a

suitably fulcrumed lever adapted to be supported in normal position by the normal pressurein said line, and a flexible connection between the said lever and the said spring member. 7 1 V 4. In apparatus of the class described, in combinatiom'a pressure line, a motor driven pressure generator therefor, a switch for said motor, a roller provided at one end with a plurality of teeth arranged circularly and having wound thereon a rope from the free end'of which a weight is suspended, a spring member normally engaging said teeth whereby rotation of the roller is prevented, a normally slack flexible connection having 7 one end. securedto the switch lever and'the other end wound on the roller, a suitably fulcrumed lever the free end of which is in connection with the said 7 spring member,

and a piston in the said pressure line maintained by normalpressure therein in positionto support saidlever, said piston and said lever being adapted to fall when the pressure in'the line falls' below normal;

5. In apparatus of the class'des cribed, in combination, a pressure line, a motordriven pressure generator therefor, a switch for said motor, a roller provided at oneend with a plurality of, teeth arranged circu- I larly and having wound thereon a rope from the free end of which a weight is sus pended, a spring member normally engag- .95 ing said teeth whereby rotation ofthe'roller V and dropping of said weightisprevented, a normally slack flexible connection having one end secured to the switch lever and the other end wound 'on the roller, a suitably fulcrumed weighte'dlever, a flexible connection between the said spring member and the weighted end of the lever, and a piston V in the pressure linel maintained by normal pressure therein in position to support the 10 weighted end of the said lever, saidpiston being adapted to drop when the pressure in the said line falls below normal.

6. 'In'apparatus of the class described, combination, a pressure line, a motordriven pressure generator therefor,..a 'switch'for said motor, a roller provided at 'one'end with a plurality of, teeth and having wound thereon a rope from the free end of which a weight is suspended, a spring membernor mally engaging said teeth whereby rotation of the roller is prevented,a normally slack flexible connection having one end' secured e to the switch lever and the other end wound on the roller, a suitably "fulcrumed vertically movable lever adapted to be supported 7 r in its highest position by the normal pres-V" sure in the said pressure line, a flexible con nection between the said lever and the said spring member, and a slotted member which the free end of said lever is vertically movable. V V r V V 7. In apparatusof the class described, in combination, a pressure line, a .motor driven pressure generator therefor, a switch for said motor, a roller provided at one end the normal pressure in the said pressure with a plurality of teeth and having wound line, a flexible connection between the said thereon a rope from the free end of which lever and the said spring member, a slotted a weight is suspended, a spring member normember in which the free end of said lever 5 mally engaging said teeth whereby rotation is vertically movable, and springs in the slot 15 of the roller is prevented, a normally slack of said slotted member disposed above and flexible connection having one end secured below the end of the said lever.

to the switch lever and the other end wound Dated at Vancouver, B. 0., this 19th day on the roller, a suitably fulcrumed vertically of May, 1917.

10 movable lever adapted to be supported by WILLIAM JACOB STARK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

